I'll always start vanilla / build-less with best intentions. In fact, I often start sans JS too if I can get away with it.

But inevitably the complexity of my projects increase. My patience with focus, refresh, review cycle crashes. My first stop is usually vite, just for hot reload at first, but then for raw imports, and I do like nested CSS. When I find myself beginning to roll my own reactivity I tend to read up on the latest state of vue and svelte and drop whichever one feels right into the mix. It goes on.

All with the best intentions.